Eyewear charging case using charge pins as communication path

ABSTRACT

A case for an eyewear device having a conductive interface includes a housing that receives the eyewear device. A multi-purpose interface, supported by the housing, includes at least one contact arranged to couple with the conductive interface of the eyewear device when the housing receives the eyewear device. Circuitry is coupled to the at least one contact and includes a processor that detects a connection of the conductive interface of the eyewear device to the multi-purpose interface of the case. The processor performs a charging process during a charge state of the case in which an electrical charge is provided at the multi-purpose interface of the case to the eyewear device. Data is exchanged with the eyewear device during a communication state of the case.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional application Ser.No. 62/725,627 entitled Eyewear Charging Case Using Charge Pins asCommunication Path, filed on Aug. 31, 2019, the contents of which areincorporated fully herein by reference.

TECHNICAL FIELD

The subject matter disclosed herein relates generally to a charging casefor an electronic device.

BACKGROUND

Electronic devices typically have integrated electronics requiring anonboard power supply in the form of a battery. A case for the electronicdevice may also include a power supply for charging the battery of theelectronic device when the electronic device is stored in the case.Improvements to charging cases for electronic devices are useful in theinterests of enhancing usability and convenience, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations, by way ofexample only, not by way of limitations. In the figures, like referencenumerals refer to the same or similar elements.

FIG. 1 depicts an isometric view of a case according to one exampleshown both open and expanded, wherein portions of the case are showncutaway to reveal internal details.

FIG. 2 depicts a schematic view of a conductive interface on an eyeweardevice in connection with a multi-purpose interface of the case.

FIG. 3 is a schematic circuit diagram showing charging circuitry thatforms a part of the case and a complimentary eyewear device to becharged by the charging circuitry of the case.

FIG. 4 is a block diagram of example hardware components of the case andeyewear device.

FIG. 5 is a flow diagram illustrating an example use of the case duringcharging and communication states.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails.

The descriptions of the exemplary embodiments that follows are intendedto be read in connection with the accompanying drawings, which are to beconsidered part of the entire written description. In the description,relative terms such as “right,” “left,” “lower,” “upper,” “horizontal,”“vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as wellas derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,”etc.) should be construed to refer to the orientation as then describedor as shown in the drawing under discussion. These relative terms arefor convenience of description and do not require that the apparatus beconstructed or operated in a particular orientation. Terms concerningattachments, coupling and the like, such as “connected” and“interconnected,” refer to a relationship wherein structures are securedor attached to one another either directly or indirectly throughintervening structures, as well as both removable or rigid attachmentsor relationships, unless expressly described otherwise.

The term “coupled” refers to any logical, optical, physical orelectrical connection, link or the like by which signals or lightproduced or supplied by one system element are imparted to anothercoupled element. Unless described otherwise, coupled elements or devicesare not necessarily directly connected to one another, and intermediatecomponents that may modify, manipulate, or carry the light or signalsmay separate elements or communication media.

FIG. 1 depicts an isometric view of an example case for receiving aneyewear device. The eyewear device may be, for example, eyeglasses,spectacles, or headgear. The case 10 is shown in an open and expandedstate, wherein portions of the case are shown cutaway to reveal internaldetails. The case 10 includes a housing 11 having an opening 12 leadingto a hollow cavity 13 that is sized and shaped to receive and hold aneyewear device when, for example, the temples of the particular eyeweardevice are in a folded state. The illustrated housing 11 includes arectangular shaped front wall 14; a rectangular shaped rear wall 16; acurved bottom wall 18 connecting the front and rear walls; a triangularshaped left wall 20 interconnecting the left-side edges of the walls 14,16 and 18; a triangular shaped right wall 22 interconnecting theright-side edges of the walls 14, 16 and 18; and a trapezoidal shapedflap 24 (also referred to herein as a cover) that extends from the topedge of the rear wall 16 for covering the opening 12 of the housing 11in a closed state of the case 10 (not shown).

The front wall 14 and the rear wall 16 each include a plurality oflayers. A series of protrusions and recesses are formed on the interiorfacing surface of the front and rear walls 14 and 16 that are sized andshaped to contact surfaces of the eyewear device (not shown) to limitmovement of the eyewear device when stowed within the case 10.

The base layer may include one or more magnets (not shown) on the frontwall 14, with a decorative material layer covering them so the magnetsare not visible to the end user. The one or more magnets may interactwith magnets embedded in the flap 24 for releasably retaining the flap24 to the front wall 14. As used herein, a magnet is a material orobject that produces a magnetic field. A magnet may be either apermanent magnet or a ferromagnetic material. A permanent magnet is anobject made from a magnetized material and that creates its ownpersistent magnetic field.

The curved bottom wall 18, which connects the front and rear walls 14and 16, includes a plurality of layers including an elasticallydeformable inner plastic layer that is covered on each side by the samedecorative layer 29 as the other walls. The curved bottom wall 18 may bereferred to herein as a mechanical spring. The natural state of thebottom wall 18 is a collapsed state. Moving the case 10 from thecollapsed state to the expanded state, in order to stow the eyeweardevice within the cavity 13 of the case 10, causes the bottom wall 18 toelastically deform in an outward direction. When either the eyeweardevice is removed from the cavity 13 of the case 10 or a force that ismanually applied to the case 10 for maintaining the case in the expandedstate is removed, the curved bottom wall 18 returns the case 10 to itsnatural collapsed. In another example, the housing of the case may be arigid, non-deformable structure.

The left and right walls 20 and 22, respectively, each may have apreformed fold 21 that is capable of being folded inwardly when the case10 is moved from the expanded state of to the collapsed state. Thetrapezoidal shaped flap 24 includes articulated and interconnectedsegments. The flap 24 includes inner facing and outer facing layers. Theinner facing and outer facing layers may be composed of a samedecorative layer as the other walls. A series of inserts are embeddedbetween the inner facing and outer facing layers of the flap 24. A firstinsert 31, positioned closest to the rear wall 16, has a rectangularshape with rounded edges and is composed of plastic. A second insert 32,positioned further from the rear wall 16, has a rectangular shape withrounded edges and is composed of a magnet that is sandwiched between twoplastic pieces. A width dimension of the second insert 32 issubstantially equal to that of the first insert 31; however, a heightdimension of the second insert 32 is substantially greater than that ofthe first insert 31. A third insert 33, which is positioned furthestfrom the rear wall 16, has a trapezoidal shape with rounded edges and isalso composed of a magnet that is sandwiched between two plastic pieces.

The magnets of the second and third inserts 32 and 33 interact with oneor more magnets (not shown) that are embedded in the front wall 14 forreleasably retaining the flap 24 to the front wall 14 in either a closedand collapsed state or a closed and expanded state of the case 10.

A connector 40, capable of transferring power (and/or signals), ismounted to the right edge of the rear wall 16. In operation, a cable 73(FIG. 3) is connected to the connector 40 for charging a battery 42within the case. Circuity within the case 10 interconnects the battery42 to the connector 40. The connector 40 may be a USB connector, forexample, or a connector having radial charge contacts. The connector 40may be essentially any electrical connector that is capable oftransferring power, and is not limited to a particular style ofconnector.

As best shown in FIGS. 1 and 2, a multi-purpose interface 44 ispositioned on an interior facing side of the rear wall 16. Themulti-purpose interface 44 protrudes into the cavity 13 of the case 10.The multi-purpose interface 44 is configured to be releasably connectedto a conductive interface on the eyewear device, e.g., conductiveinterface 49 on the temple 50 of the eyewear device 52 for charging abattery in the eyewear device using the battery of the case 10. Themulti-purpose interface 44 includes, for example, a plastic housingfastened to a base layer of the front wall 14 by screws or adhesive, forexample. A shoulder 46 that is formed on the multi-purpose interface 44,forms a shelf upon which the temple 50 of the eyewear device 52 can bepositioned. At least one contact is arranged to couple with theconductive interface 49. As illustrated in FIG. 2, two electricalcontacts 54 are disposed within the multi-purpose interface 44 forinteracting with the conductive interface 49 of the eyewear device 52.The electrical contact 54 are electrically connected to the battery 42of the case 10 for receiving power therefrom, and transferring thatpower to the conductive interface 49 of the eyewear device 52.

In one example, each electrical contact 54 of the case 10 is a pogo-pinstyle contact that is biased outwardly by an internal spring 55. In anassembled form of the case 10, the spring 55 biases the contact 54outwardly toward the conductive interface 49 disposed on the temple 50of the eyewear device 52. The outwardly biasing action of the spring 55helps to ensure sufficient surface contact between the electricalcontacts 54 of the case 10 and the conductive interface 49 of theeyewear device 52 so that electricity can be reliably transferred fromthe battery 42 of the case 10 to the internal battery (not shown) of theeyewear device 52. Suitable pogo-pin style contacts are distributed bythe Mill-Max Corporation of New York, USA.

Magnets 58 of the multi-purpose interface 44 of the case are positionedon either side of the electrical contacts 54. The magnets 58 interactwith magnets 60 disposed on the temple 50 of the eyewear device 52. Themagnetic force between the magnets 58 and 60 is sufficiently greaterthan the spring force of the electrical contact 54 to ensure that thetemple 50 of the eyewear device 52 remains connected to the connector 44of the case 10 while the springs 55 bias the temple 50 of the eyeweardevice 52 away from the case 10. One set of the two sets of magnets 58and 60 could be a permanent magnet, whereas the other set of the twosets of magnets 58 and 60 could be ferromagnetic.

The adjacent magnets 58 have opposite polarity (as indicated by theNorth (N) and South (S) designations), and the adjacent magnets 60 alsohave opposite polarity, to provide an even stronger attraction betweenthe mating magnets.

A display or indicator in the form of a plurality of lights 66 (fourshown) are disposed on the interior facing side of the rear wall 16. Thelights 66 may be LED lights. The lights 66 illuminate to represent thepower remaining in the battery 42 of the case 10. For example, if thebattery 42 is fully charged, then all four lights 66 are illuminated.Whereas, if the battery 42 is significantly depleted then one light 66is illuminated. The lights 66 are illuminated only when the flap 34 isopen thereby conserving battery power. It should be understood that thedisplay may vary from that which is shown and described. For example,the display could comprise a single light that is capable ofilluminating different colors, e.g., green indicating a full charge andred indicating a low charge or no charge. Various other suitabledisplays are known to those skilled in the art.

FIG. 3 is a schematic circuit diagram showing charging circuitryincluded in the case 10 and the complimentary eyewear device 52 forcharging during a charging state and communication of data during acommunication state. In the example illustrate by FIG. 3, the battery 42of the case 10 is coupled to the conductive interface 49 of the eyeweardevice 52. The battery 42, charging contact 54, and the conductive pathsbetween them together form an interrupted charging circuit that can becompleted by the eyewear device 52 via contact engagement of therespective conductive interface 49 of the eyewear device 52 with thecorresponding charging contacts 54 of the case 10.

As shown schematically in FIG. 3 in broken lines, the onboardelectronics of the eyewear device 52 includes charging circuitryconnecting the conductive interface 49 to the onboard battery 71 of theeyewear device 52. The internal charging circuitry is configured tocause charging of the onboard battery 71 when a voltage difference withthe illustrated polarity is applied over the conductive interface 49.

The case battery 42 is connected to the charging connector port 40incorporated in the case 10. The case 10 thus includes a chargingcircuit option for the case battery 42, in this example by connection tothe mains power via a charging cable 73 removably connectable to thecharging port 40. In some examples, the charging circuit of the case 10is configured such that connection to mains power via the charging port40 while the eyewear device 52 are connected to the charging circuit(such as in FIG. 3) resulting in charging of the onboard battery of theeyewear device 52 by mains power.

When the eyewear device 52 is located in the case 10 in a chargingconfiguration such that the conductive interface 49 is coupled to therespective charging contacts 54, the onboard battery 71 of the eyeweardevice 52 is automatically recharged by the battery 42 of the case 10(or, if the case 10 is connected to mains power by a charging cable 73,the glasses battery 71 is recharged by mains power). A processor 80 isconnected to the power circuit and the lights 66. The processor 80receives the charge state of the case battery 42 through the powercircuit.

FIG. 4 is a block diagram of an example of the hardware components ofthe charging case and eyewear device.

The block diagram 400 of FIG. 4 includes a case 402 and eyewear device404 such as described in FIGS. 1 and 2 above. The hardware componentsarranged within the housing of the case 402 include, for example, aprocessor 410 for controlling components in the case 402, circuitry 422such as, for example, a negative channel field effect transistor (NFET)protection circuit to protect the case 402 from current drain andcorrosion when a device is not connected and there are mismatched I/Ovoltage connections to the case 402.

The housing of the case 402 supports a multi-purpose interface 406. Themulti-purpose interface 406 includes at least one contact configured toconnect or couple with, for example, the eyewear device 404, via aconductive interface 408 of the eyewear device 404 for charging of thebattery 420 of the eyewear device 404 and/or data communication betweenthe case 402 and eyewear device 404. The processor 410 of case 402 and aprocessor 416 of the eyewear device may each include a communicationcomponent using a single-wire communication protocol, for example, aUniversal Asynchronous Receiver/Transmitter (UART) configured totransmit and receive data for the exchange of data between the case 402and the eyewear device 404 over a single wire. Charging case 402 mayfurther include a switching device, controlled by the processor 410, andcoupled to the circuitry 422 and a power supply 414. In FIG. 4, anexample 5-volt dc power supply is illustrated; however, the power supply414 is not limited to this value.

The electronic components of the eyewear device 404 include, forexample, a processor 416 for controlling components of the eyeweardevice 404, a battery 420 for powering the components of the eyeweardevice 404, a switching device 419 coupled to the battery and circuitrysuch as field effect transistors, for example, an NFET protectioncircuit to protect the eyewear device from mismatched I/O connections toother devices. Eyewear device 404 further includes a conductiveinterface 408 that includes charge pads arranged for coupling to themulti-purpose interface 406 of the charging case 402. The at least onecontact of the multi-purpose interface of the charging case 402 includesa first contact corresponding to a first charge pad of the conductiveinterface 408 and a second contact corresponding to a second charge padof the conductive interface 408 of the eyewear device 404. Although notillustrated in FIG. 4, the eyewear device may further include variouscomponents common to mobile electronic devices such as eyewear devicesor smartphones, for example, a display controller for controllingdisplay of visual media, a wireless module (e.g., Bluetooth™) forcommunication between the eyewear device 404 and a mobile device such asa smartphone, tablet device or server, a camera, flash storage forstoring data (e.g., images, video, image processing software, etc.), andLEDs which may be configured to provide visual operation feedback to auser of the eyewear device 404.

The processor 410 of the charging case 402 is configured to detect aconnection of the conductive interface 408 of the eyewear device 404 tothe multi-purpose interface 406. In order to detect the connection ofthe conductive interface 408 to the multi-purpose interface 406, voltagelevels at pins, for example, pogo pins, of the multi-purpose interface406 and conductive interface 408, are monitored and analyzed by theprocessor 410. In an example, the voltage levels vary between 0 voltsand a drain supply voltage VDD based upon, for example, a connection ofthe conductive interface 408 of the eyewear device 404 to themulti-purpose interface 406 of the case 402.

As illustrated in FIG. 4, circuitry 422 includes a first pull-upresistor having, for example, a resistance of 470K ohms, and a secondpull-up resistor having, for example, a resistance of 4.7K ohms. Whenthe switch 412 is in an open position, a first voltage level at themulti-purpose interface 406 varies based upon a connection state of thepull-up resistors. Table 1 provides examples of the various digital andanalog voltage levels VDD at the multi-purpose interface 406 of the case402 based upon the pull-up resistor values illustrated in FIG. 4. Thepull-up resistor values of 470K ohms and 4.7K ohms are provided only asexamples. One of ordinary skill in the art will recognize that otherresistor values may be used.

TABLE 1 Specs Short Between Digital Voltage ADC Case Pull Up ConnectedPins at Pin [0 or 1] Reading [V] 470k No No 1.00 3.00 470k Yes No 0.000.27  4.7k No No 1.00 3.00  4.7k Yes No 1.00 2.73 470k Yes Yes 0.00 0.10 4.7k Yes Yes 0.00 0.10

In an example, when the switch 412 is in an open position, and theeyewear device 404 is not connected to the multi-purpose interface 406,a voltage level with the 470K pull-up resistor is 3.0 volts when thereis no short between the pins of the multi-purpose interface 406. Whenthe eyewear device 404 is connected at the multi-purpose interface 406(and there is no short at the pins), a voltage level of the case withpull-up resistor 470K ohm is 0.27 volts. The eyewear device 404 includesa pull-down resistor having a weak pull-down value, for example, 47Kohms. When the eyewear device 404, having the 47 k ohm pull-downresistor, is detected at the multi-purpose interface 406, a voltagelevel of the case 402 is 2.73 volts. When a voltage level is measuredthat is less than the first voltage level known for when no eyeweardevice 404 is connected to the multi-purpose interface 406, for example,less than 3.0 volts, the processor is able to determine whether there isa short between the pins which results in a minimal voltage level, forexample, 0-0.10 volts, or the eyewear device 404 is connected to themulti-purpose interface 406, i.e., the process detects the connection ofthe conductive interface 408 of the eyewear device 404 to themulti-purpose interface 406 of the case 402. As illustrated in Table 1,when the eyewear device 404 is connected to the multi-purpose interface406 of the case, a voltage level may vary between 0.27 volts-2.73 volts.Upon the detection of the connection of the eyewear device 404, theprocessor 410 sends a signal to close the switching device 412, andinitiates the charging process during a charge state of the case 402. Anelectrical charge is provided at the multi-purpose interface 406 tocharge the battery 420 of the eyewear device 404 during the chargestate.

In an another example for detecting and confirming a connection of theconductive interface 408 of the eyewear device 404 to the multi-purposeinterface 406, additional pull-up resistors, for example the secondresistor in the case 402 illustrated in FIG. 4 having a value of 4.7Kohms, may be used to obtain digital or analog to digital converter (ADC)measurements to determine whether the pull-down from the first voltagelevel of 3.0-volts is the result of the connection of eyewear device 404as opposed to an unexpected electrical short, etc. For example, asprovided in Table 1, when the switch 412 is in an open position, and theeyewear device 404 is not connected, a voltage level of the case 402 atthe 4.7 k pull-up resistor is 3.0 volts. When the eyewear device 404 isconnected, a voltage level of the case using the second pull-upresistor, 4.7 k, is 2.73 volts.

Upon completion of the charge state of the case 402, processor 410 maysend a signal to open the switch 412 so that charging is discontinued,and initiate a half-duplex communication state, for example, via theUART, in which the case 402 is synchronized with the eyewear device anddata is exchanged between eyewear device 404 and the case 402 via theconnection of the conductive interface 408 to the multi-purposeinterface 406. The data exchanged may include, for example, case usagestatistics, battery efficiency statistics, or a charge level of the case402.

Using time multiplexing, the multi-purpose interface 406 of the case 402can perform both functions of charging the battery 420 of the eyeweardevice 404 and exchanging digital communications. During the chargestate of the case 402, no communication occurs. At the end of the chargestate, using, for example, a single-wire half-duplex communicationprotocol, for example a UART communication protocol, data may beexchanged between the case 402 and the eyewear device 404. The case 402may transition periodically between a charging state and a communicationstate, e.g., under control of the processor 410.

FIG. 5 is a flow diagram illustrating an example of the use of thecharging case during charging and communication states.

In the example of FIG. 5, the case 402 at step 502 includes componentssimilarly described above, for example, in FIG. 4. At step 502, the case402 is idle and the charge state of the case 402 is inactive. At step504, while the case 402 awaits detection of the connection of, forexample, the eyewear device 404, the switch 412 is in an open positionsuch that the power supply 414 is not connected. The connection of theeyewear device 404 to the charging case 402, as described above,includes detecting a connection of the conductive interface 408 to atleast one contact of the multi-purpose interface 406 of the chargingcase 402, where the multi-purpose interface may consist of a firstcontact corresponding to a first charge pad of the conductive interfaceand a second contact corresponding to a second charge pad of theconductive interface of the eyewear device. When the processor of thecharging device detects the connection of the eyewear device, theprocess moves to step 506.

At step 506, the processor of the charging case sends a signal to theswitch 412 to change the switch to a closed position, and initiates acharging process during a charge state of the case. The charge state ofthe case has an initial charging period having a first fixed time, forexample, approximately 500 msec, starting upon the detection of theconnection of the contact pads of the conductive interface of theeyewear device to at least one contact of the multi-purpose interface ofthe charging case, and ending with a first charge interrupt signal.After the first charge interrupt signal, the switching device of thecharging case is switched to an open position to disconnect the powersupply and end the charging state. The process moves to step 508.

At step 508, the processor of the case initiates a communication stateduring which data is exchanged between the charging case and the eyeweardevice, and the connected eyewear device awaits receipt of data from thecase. Data is transmitted, for a first predetermined time of thecommunication state, for example, 10 msec, to the eyewear device using acommunication protocol such as the UART protocol of the processor of thecharging device. The process moves to step 510.

At step 510, the eyewear device sends data to the charging device for asecond predetermined time of the communication state, for example, 10msec, using a half-duplex communication protocol such as the UART of theprocessor of the eyewear device. The process returns to step 508.

The exchange of data during the communication state of the casecontinues during steps 508 and 510, which are repeated for apredetermined duration, for example approximately 50 msec with each datapacket (case-to eyewear device or eyewear device to case) being lessthan approximately 10 msec, that ends the communication state. When thecommunication state of the case ends, the process returns to step 502.If the eyewear device has a completely charged or desired battery chargelevel, the battery status of the eyewear device 404 is communicated tothe case 402 using the UART protocol, and the conductive interface ofthe eyewear device may be disconnected from the multi-purpose interfaceof the charging device. The process then ends with the case 402 enteringa low power mode or power off mode.

The eyewear device 404 may be stowed in the case 402. When stowed, theweaker pull-up resistance, for example, the 470 k ohm resistor, of case402 is activated. During the duration of the eyewear device 404 beingpositioned or stowed within the case 402, the 47 k ohm pull-downresistance of the eyewear device 404 will dominate to cause the voltagelevel at the multi-purpose interface 406 of the case 402 to be lowrelative to the Vdd voltage level of 3.0 volts for the 470 k ohm pull-upresistance when the eyewear device 404 is not connected. The low voltagelevel measurement at the multi-purpose interface 406 may be, forexample, 0.27 volts, as provided in Table 1 when the pull-up resistanceis 470 k ohm and the eyewear device 404 is connected. When the eyeweardevice 404 is removed from the case 402 the voltage level at themulti-purpose interface 406 of the case 402 will float high, forexample, 3.0 volts, and the processor 410 can quickly detect that theeyewear device 404 is removed based upon the increased voltage level atthe multi-purpose interface 406.

It is to be understood that the steps of the processes described hereinare performed by a processor upon loading and executing software code orinstructions which are tangibly stored on a tangible computer readablemedium, such as on a magnetic medium, e.g., a computer hard drive, anoptical medium, e.g., an optical disc, solid-state memory, e.g., flashmemory, or other storage media known in the art. Thus, any of thefunctionality performed by the processor described herein is implementedin software code or instructions which are tangibly stored on a tangiblecomputer readable medium. Upon loading and executing such software codeor instructions by the processor, the processor may perform any of thefunctionalities described herein, including any steps of the methodsdescribed herein.

The term “software code” or “code” used herein refers to anyinstructions or set of instructions that influence the operation of acomputer or controller. They may exist in a computer-executable form,such as machine code, which is the set of instructions and data directlyexecuted by a computer's central processing unit or by a controller, ahuman-understandable form, such as source code, which may be compiled inorder to be executed by a computer's central processing unit or by acontroller, or an intermediate form, such as object code, which isproduced by a compiler. As used herein, the term “software code” or“code” also includes any human-understandable computer instructions orset of instructions, e.g., a script, that may be executed on the flywith the aid of an interpreter executed by a computer's centralprocessing unit or by a controller.

Although an overview of the inventive subject matter has been describedwith reference to specific examples, various modifications and changesmay be made to these examples without departing from the broader scopeof examples of the present disclosure. For example, although thedescription focuses on an eyewear device, other electronic devices suchas headphones are considered within the scope of the inventive subjectmatter. Such examples of the inventive subject matter may be referred toherein, individually or collectively, by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single disclosure or inventive concept if more thanone is, in fact, disclosed.

The examples illustrated herein are described in sufficient detail toenable those skilled in the art to practice the teachings disclosed.Other examples may be used and derived therefrom, such that structuraland logical substitutions and changes may be made without departing fromthe scope of this disclosure. The Detailed Description, therefore, isnot to be taken in a limiting sense, and the scope of various examplesis defined only by the appended claims, along with the full range ofequivalents to which such claims are entitled.

What is claimed is:
 1. A case for an eyewear device having a conductiveinterface, the case comprising: a housing configured to receive theeyewear device; a multi-purpose interface supported by the housing, themulti-purpose interface comprising at least one contact arranged tocouple with the conductive interface of the eyewear device when theeyewear device is received by the housing; circuitry coupled to the atleast one contact and including a processor configured to: detect aconnection of the conductive interface of the eyewear device to themulti-purpose interface of the case in response to detection of apredetermined difference between a pull-up signal at the multi-purposeinterface of the case and a pull-down signal at the multi-purposeinterface; perform a charging process during a charge state of the casewhere an electrical charge is provided at the multi-purpose interface ofthe case to the eyewear device; and exchange data with the eyeweardevice, via the multi-purpose interface, during a communication state ofthe case.
 2. The case of claim 1, wherein the at least one contact ofthe multi-purpose interface consists of a first contact corresponding toa first charge pad of the conductive interface and a second contactcorresponding to a second charge pad of the conductive interface.
 3. Thecase of claim 1, wherein the processor is configured to initiate thecharging process in response to the detected connection of the eyeweardevice.
 4. The case of claim 3, wherein to detect the eyewear device theprocessor is configured to: connect a first pull-up resistance to themulti-purpose interface; detect a first voltage level during theconnection of the first pull-up resistance; connect a second pull-upresistance to the multi-purpose interface; detect a second voltage levelduring the connection of the second pull-up resistance; and detect theeyewear device when at least one of the first voltage level or thesecond voltage level is below a predefined voltage level.
 5. The case ofclaim 1, wherein the charge state has an initial charging period havinga first fixed time starting upon the detection of the connection of theeyewear device to the multi-purpose interface and ending with a firstcharge interrupt signal.
 6. The case of claim 1, further comprising aswitching device coupled to the circuitry to supply a dc voltage to thecase.
 7. The case of claim 1, wherein the processor is furtherconfigured to synchronize the case with the eyewear device and toperiodically switch between the charge state and the communicationstate.
 8. The case of claim 1, wherein the processor includes aUniversal Asynchronous Receiver/Transmitter (UART) component configuredto transmit and receive data with the eyewear device via themulti-purpose interface.
 9. A system, comprising: an eyewear deviceincluding a conductive interface; a case configured to receive theeyewear device; the case comprising: a housing configured to receive theeyewear device; a multi-purpose interface supported by the housing, themulti-purpose interface comprising at least one contact arranged tocouple with the conductive interface of the eyewear device when theeyewear device is received by the housing; circuitry coupled to the atleast one contact and including a processor configured to: detect aconnection of the conductive interface of the eyewear device to themulti-purpose interface of the case in response to detection of apredetermined difference between a pull-up signal at the multi-purposeinterface of the case and a pull-down signal at the multi-purposeinterface; perform a charging process during a charge state of the casewhere an electrical charge is provided at the multi-purpose interface ofthe case to the eyewear device; and exchange data with the eyeweardevice via the multi-purpose interface during a communication state ofthe case.
 10. The system of claim 9, wherein the processor is configuredto initiate the charging process in response to the detected connectionof the eyewear device.
 11. The system of claim 10, to detect the eyeweardevice the processor is configured to: connect a first pull-upresistance to the multi-purpose interface; detect a first voltage levelduring the connection of the first pull-up resistance; connect a secondpull-up resistance to the multi-purpose interface; detect a secondvoltage level during the connection of the second pull-up resistance;and detect the eyewear device when at least one of the first voltagelevel or the second voltage level is below a predefined voltage level.12. The system of claim 9, wherein the at least one contact of themulti-purpose interface consists of a first contact corresponding to afirst charge pad of the conductive surface and a second contactcorresponding to a second charge pad of the conductive interface. 13.The system of claim 9, further comprising a switching device coupled tothe circuitry to supply a dc voltage to the case.
 14. The system ofclaim 9, wherein the charge state of the case has an initial chargingperiod having a first fixed time starting upon the detection of theconnection of the eyewear device to the multi-purpose interface andending with a first charge interrupt signal.
 15. The system of claim 9,wherein the processor of the case is further configured to synchronizethe case with the eyewear device and to periodically switch between thecharge state and the communication state.
 16. A method comprising:detecting a connection of an eyewear device having a conductiveinterface to a multi-purpose interface of a case in response todetection of a predetermined difference between a pull-up signal at themulti-purpose interface of the case and a pull-down signal at themulti-purpose interface, wherein the multi-purpose interface issupported by a housing of the case, and wherein the multi-purposeinterface comprises at least one contact arranged to couple with theconductive interface of the eyewear device; performing a chargingprocess during a charge state of the case where an electrical charge isprovided at the multi-purpose interface of the case to the eyeweardevice; and exchanging data with the eyewear device via themulti-purpose interface during a communication state of the case. 17.The method of claim 16, wherein the performing the charging process isinitiated in response to the detected connection of the eyewear deviceto the multi-purpose interface.
 18. The method of claim 16, furthercomprising: synchronizing the case with the eyewear device andperiodically switching between the charge state and the communicationstate.